Helical spring



May 14, 1935. Y J. w. ROCKEFELLR, JR 2,000,905

HELICAL SPRING Filed Sept. l, 1953 s "I: .i -4. l :1 INVENTOR JOHN W. ROCKEFELLEKJR.

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O O O 5 ATTORNEY` DEFLECTION IN INCHES I: sci Z.

- Patented May 1.4K, 1935 l UNIT-ED STATES PAT-ENI OFFICE;

' HEHS'WG i John W. Rockefeller, Jr., New York, N. Y.

Application September 1, 1933., Serial No. 681,749`

9 Claims.

It has been recognized that a coilspring haswhen normallyv designed, a substantially straight line characteristic, and`it has further been recognized that such straight line characteristic is objectionable in many instances. For example, coil springs are often made heavier than-the duty requires, or are lsupplemented by leaf springs in series or in parallel, in order to change the characteristic, or are made o! varying diameter, or pitch, or both in` order to modify such inherently objectionable characteristic. It is also known, as for instance in coil compr/esslon springs used in railway trucks, especially high speed, thatthe natural period of vibrationV synchronizes ,with the vertical Vtruck movements due to .rail joints, irregularities in the track, etc., thereby building up harmonic vibrations until the springs go solid or break. 'I'he purpose of combining leaf springs with coil springs has been to alter the normal characteristic, and reduce or suppress harmonics. According to this invention, the normal characteristic of a coil spring is altered by varying its torsion during a predetermined portion o! its variation in length, whereby its normal straight line characteristic is modied, and also a spring of given size rendered capable of sustaining a greater load. In general, I accomplish this by so mounting a coil spring subject to compression or extension, that, as its length is varied, its torsion is varied either by winding up or unwinding. This result is conveniently eiected in the simple illustrative embodiment herein shown by a relatively tlxed cam which varies the torsion oi the spring as `its length varies, and gives the spring a resultantL controllable characteristic varying with the design of the cam. A coil spring embodying this invention can be converted into an ordinary spring by disconnecting the cam so that it becomes inoperative to control the torsion of the spring.

In the accompanying drawing: Fig. 1 is a view partly in section of a spring embodylng the invention, suitable for insertion in a car truck, for example, in place of a ,standard coil spring;

Fig. 2 is a similar view of a modification; Fig. 3 is a diagram showing characteristics of .two standard coil springs, and the modiiied characteristics effected with this invention; and

Fig. 4 shows a .modification in which torsion applied to the spring effects compression. 1

.. fixed block 29 having cam groove 30 in which workslpinrl on tube 21;

In Fig.A l, I is a'coiled spring of circular, oval or other desired cross section, having oneI end '2 anchored in plate 3 andthe opposite end 4 anchored in plate 5, which is rotatably connected,

as by pin 6, to plate 1. For some uses, it may be '5;

desirable tol provide roll or ball bearings between plates 5 and 1. Plate 5 carries an extension 8 within the coil I which carries pin 9 sliding in the grooves Ill of cam body Il which is centered on plate 3 byy pin I2. Thevcam II is held against rotation by detachable pins I3 passing through plate 3 into the cam body. When pins I3 are rev moved, the cam can rotate as the spring is compressed or'lengthened and tlus becomes ineffective, leaving the device an ordinary spring. When the pins I3 are connected as shown, the cam is xed, and shorteningu or lengthening of the spring will cause the spring to wind or unwind, depending upon the design of the cam, the degree of deection and direction of motion, by reason of the plate 5, turning on plate 1'. As shown in the drawing the spring winds up when compressed owing to the relation of the cam curve to the coil of the spring. Ifv it is desired to unwind the spring when compressed, the cam curve would be reversed. c In Fig. 2 is shown a moditlcation wherein the cam curve alternately winds and unwinds the spring during compression by means of specially designed cam I5 having slots I1 in which travel the pins I8 mounted oncylinder I9. 20 is the rotary end plate turning in stationary plate 2|, and opposite plate 22 is also stationary.

Fig. 3 shows thel characteristics of several springs, in whichA is thecharacteristic of an -A. R. A. inner railway truck spring; B an A. R. A. outer spring, C the combination of A and. B together iny one truck, and Dthe varying characteristic of the single spring of Fig. 2. `This gure shows graphically how the normal straight line characteristic of a coil spring can be varied at any desired point by the -proper'design of the cam. y y

. In Fig. 4, the torsion spring I has one end 2| stationary in plate 25, and its other .end 26. rotatable bymeans of tube 2l having actuating lug 28 to which rotary movement is applied by any suitable means not shown. On the base is This arrangement of cam.will give a torsion characteristic similar' to the portion D of Fig. 3, but can be designed to give any other desired characteristic."

Useful applications of this invention will be in railroad car suspension, automobile suspension, automobile shock absorbers, automobile valve springs, door checks and closers, vibration elimination devices, even tension devices, window springs, draw bar springs, automatic controlling devices, safety valves (boiler and other pressure vessels), shade roller and metal door roller springs, spring hinges, ammunition springs, brush holder springs, recording gauge springs and numerous other devices employing coil springs where a variable characteristic vis desired.

Various modifications and changes may be made without departing from' the scope of the appended claims. f

The invention claimed is:

1. A helical spring in combination with means for `automatically torquing and untorquing same as the spring is progressively deflected axially.`

2. A helical spring in combination with means for automatically torquing and untorquing same as the spring is progressively extended.

3. A helical spring in combination with means for automatically torquing same during its initial stages of axial deflection and reducing torque during its later stages of axial deection.

4. A helical spring in combination with means for automatically torquing and untorquing same in such manner as to give a varying and predetermined increment of axial deflection for a given increment of axial loading at diierent stages of axial deflection.

5. A helical compression spring in combination with means for torquing same during its initial stages of compression and untorquing same during its -later stages of compression in such manner as to create a high stress in the material during the initial stages of compression and a relatively small increase in stress during the later stages.

6. A helical torsion spring having one end subject to torsion and the other end xed, and cam means for torquing and untorquin'g the spring as it is axially deected.

7. In a spring mounting, a helical spring unconiined for substantial radial expansion and contraction, means for automatically torquing the spring during its initial stages of axial deflection and reducing torque during its later stages of axial deflection.

8. A helical spring in combination wth means for automatically torquing the same as it is deected. axially, said means producing through a variable torquing resistance a substantial and predetermined modification of the ordinary straight line load deflection characteristic of they spring. A

' 9. A helical spring in combination with means forautomatically torquing same as it is deected axially, said means eecting torsion at such a variable rate as to produce by means of torquing resistance'a spring combination having a high axial resistance under lesser loads and a lower axial resistance under greater loads.

JOI-IN W. ROCKEFELLER, JR. 

